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2022 ◽  
pp. 1-30
Author(s):  
Bruno A. Santos ◽  
Rogerio M. Gomes ◽  
Xabier E. Barandiaran ◽  
Phil Husbands

Abstract A growing body of work has demonstrated the importance of ongoing oscillatory neural activity in sensory processing and the generation of sensorimotor behaviors. It has been shown, for several different brain areas, that sensory-evoked neural oscillations are generated from the modulation by sensory inputs of inherent self-sustained neural activity (SSA). This letter contributes to that strand of research by introducing a methodology to investigate how much of the sensory-evoked oscillatory activity is generated by SSA and how much is generated by sensory inputs within the context of sensorimotor behavior in a computational model. We develop an abstract model consisting of a network of three Kuramoto oscillators controlling the behavior of a simulated agent performing a categorical perception task. The effects of sensory inputs and SSAs on sensory-evoked oscillations are quantified by the cross product of velocity vectors in the phase space of the network under different conditions (disconnected without input, connected without input, and connected with input). We found that while the agent is carrying out the task, sensory-evoked activity is predominantly generated by SSA (93.10%) with much less influence from sensory inputs (6.90%). Furthermore, the influence of sensory inputs can be reduced by 10.4% (from 6.90% to 6.18%) with a decay in the agent's performance of only 2%. A dynamical analysis shows how sensory-evoked oscillations are generated from a dynamic coupling between the level of sensitivity of the network and the intensity of the input signals. This work may suggest interesting directions for neurophysiological experiments investigating how self-sustained neural activity influences sensory input processing, and ultimately affects behavior.


Author(s):  
Suchana Mishra ◽  
Rabindra Kishore Mishra ◽  
Srikanta Patnaik

This paper deals with a rectangular microstrip antenna on a trapezoidal substrate. It finds radiation pattern of the antenna using the concept of fractional cross product. Results show that as the fraction goes from 1 to 0.1, the direction of null in the H-plane moves from end fire towards broad side. Also, a back-lobe starts to appear in the H-plane.


2021 ◽  
Vol 922 (2) ◽  
pp. L38
Author(s):  
Christopher F. Chyba ◽  
Kevin P. Hand

Abstract Two forms of ohmic heating of astrophysical secondaries have received particular attention: unipolar-generator heating with currents running between the primary and secondary, and magnetic induction heating due to the primary’s time-varying field. Neither appears to cause significant dissipation in the contemporary solar system. But these discussions have overlooked heating derived from the spatial variation of the primary’s field across the interior of the secondary. This leads to Lorentz-force-driven currents around paths entirely internal to the secondary, with resulting ohmic heating. We examine three ways to drive such currents, by the cross product of (1) the secondary’s azimuthal orbital velocity with the nonaxially symmetric field of the primary, (2) the radial velocity (due to nonzero eccentricity) of the secondary with the primary’s field, or (3) the out-of-plane velocity (due to nonzero inclination) with the primary’s field. The first of these operates even for a spin-locked secondary whose orbit has zero eccentricity, in strong contrast to tidal dissipation. We show that Jupiter’s moon Io today could dissipate about 600 GW (more than likely current radiogenic heating) in the outer 100 m of its metallic core by this mechanism. Had Io ever been at 3 Jovian radii instead of its current 5.9, it could have been dissipating 15,000 GW. Ohmic dissipation provides a mechanism that could operate in any solar system to drive inward migration of secondaries that then necessarily comes to a halt upon reaching a sufficiently close distance to the primary.


2021 ◽  
Vol 61 ◽  
pp. 17-40
Author(s):  
Mikhail V. Kharinov ◽  

In this paper, aiming to develop the group and out-of-group formalization of the symmetry concept, the preservation of a matrix symmetry after row permutation is considered by the example of the maximally permutable \emph{normalized} Hadamard matrices which row and column elements are either plus or minus one. These matrices are used to extend the additive decomposition of a linear operator into symmetric and skew-symmetric parts using several commuting operations of the Hermitian conjugation type, for the quaternionic generalization of a vector cross product, as well as for creating educational puzzles and other applications.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Han Xue ◽  
Weicheng Zhang ◽  
Chao Ni ◽  
Xiping Lu

An improved Graham scan convex hull algorithm is designed using the convex hull region shrinkage algorithm and the sample selection decision algorithm. In the sorting of Graham scan convex hull algorithm, the cross-multiplication method is used instead of the operation of finding the polar angle, which avoids the high computational complexity of finding the inverse trigonometric function. When the polar angles are the same, that is, the two points are collinear, the points close to each other are deleted directly. Select the maximal horizontal ordinate point, minimal horizontal ordinate point, maximal longitudinal coordinate point, and minimal longitudinal coordinate point. Connect these points and obtain lines. The whole plane is divided into different regions. The points that are not on the convex hull are deleted, and the redundant points are removed. This can speed up the calculation of approximate convex hull boundary and shorten the time of convex hull calculation. The proposed algorithm is used for buoy drifting area demarcating. The offsets of the geometric center of the high-frequency position point and the distance from geometric center of high-frequency position of buoy to sinking stone are calculated. The experimental results show that the new algorithm can effectively accelerate the convex hull calculation. We use the convex hull process to compute the area of the drifting buoy position and discover that the drift area of the port hand buoy is similar. The drift area of the port hand buoys is similar. The drift area of the port hand buoy is greater than that of the port hand buoy.


Genus ◽  
2021 ◽  
Vol 77 (1) ◽  
Author(s):  
Robert Schoen

AbstractThe risk of many demographic events varies by both current state and duration in that state. However, the use of such semi-Markov models has been substantially constrained by data limitations. Here, a new specification of the semi-Markov transition probability matrix in terms of the underlying rates is provided, and a general procedure is developed to estimate semi-Markov probabilities and rates from adjacent population data.Multistate models recognizing marriage and divorce by duration in state are constructed for United States Females, 1995. The results show that recognizing duration in the married and divorced states adds significantly to the model’s analytical value. Extending the constant-α method to semi-Markov models, 2000–2005 U.S. population data and 1995 cross-product ratios are employed to estimate 2000–2005 duration-dependent transfer probabilities and rates.The present analyses provide new relationships between probabilities and rates in semi-Markov models. Extending the constant cross-product ratio estimation approach opens new sources of data and expands the range of data susceptible to state-duration analyses.


2021 ◽  
Vol 27 (5) ◽  
pp. 1146-1151
Author(s):  
Kee-Young Lee ◽  
Min-Kyung Kim ◽  
Jeong-Hee Kim

Recently, the issue of the harmful effects of nail care products has been posed. In case of cuticle remover, information on hazards of chemical substances is limited and product safety reports are also insufficient. This study evaluated the safety of the top three commercially selling cuticle removers that are widely used in nail care: Blue cross, Zero cleanser and Flower vita cuticle cares. To measure the pH level of cuticle remover cosmetics, distilled water and DMEM. The toxic effect of cuticle removers on cultured HaCaT was identified by MTT-assay. The patch test was performed to evaluate the occurrence of erythema on the patch area according to the criteria of ICDRG after applying the cuticle remover cosmetics (as is). Adherence to the cosmetic pH measurement guidelines, it w as confirmed that the blue cross product did not meet the pH standard of the final product of the domestic cosmetic method. When measuring the pH by diluting DMEM with a solvent, Flower vita product maintained a pH close to Neutral 7.0 overall. All three cuticle removers demonstrated dose-dependent cytotoxic on HaCaT cell. The viability of cells treated with 10 μg/mL Blue cross or 10 μg/mL Zero cleanser was presented below 10%. Otherwise, Flower vita treatment at concentrations of 0.5~20 μg up to 20 μg/mL did not affect the viability (above 70%) in the HaCaT. Of the patch test, there was positive in one case (3.3%) at 2 weeks. It was observed that a doubful reaction (-/+) to Flower vita and weak positive reactions (+) to Blue cross, and zero cleanser. Taken together, it was shown that the Flower vita product have the lowest cytotoxicity in HaCaT cells and slight allergic reaction, proving more safer than other tw o products in vivo and in vitro.


Machines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 245
Author(s):  
Camilo Andres Manrique-Escobar ◽  
Carmine Maria Pappalardo ◽  
Domenico Guida

In this investigation, a closed-chain kinematic model for two-wheeled vehicles is devised. The kinematic model developed in this work is general and, therefore, it is suitable for describing the complex geometry of the motion of both bicycles and motorcycles. Since the proposed kinematic model is systematically developed in the paper by employing a sound multibody system approach, which is grounded on the use of a straightforward closed-chain kinematic description, it allows for readily evaluating the effectiveness of two alternative methods to formulate the wheel-road contact constraints. The methods employed for this purpose are a technique based on the geometry of the vector cross-product and a strategy based on a simple surface parameterization of the front wheel. To this end, considering a kinematically driven vehicle system, a comparative analysis is performed to analyze the geometry of the contact between the front wheel of the vehicle and the ground, which represents a fundamental problem in the study of the motion of two-wheeled vehicles in general. Subsequently, an exhaustive and extensive numerical analysis, based on the systematic multibody approach mentioned before, is carried out in this work to study the system kinematics in detail. Furthermore, the orientation of the front assembly, which includes the frontal fork, the handlebars, and the front wheel in a seamless subsystem, is implicitly formulated through the definition of three successive rotations, and this approach is used to propose an explicit formulation of its inherent set of Euler angles. In general, the numerical results developed in the present work compare favorably with those found in the literature about vehicle kinematics and contact geometry.


2021 ◽  
Vol 23 (2) ◽  
pp. 12-15
Author(s):  
Stacy Magedanz

Gale Literature Criticism provides a (potentially) wide selection of literature criticism articles and original interpretive materials appropriate for undergraduates. Its interface is generally friendly and easy to use, but libraries heavily invested in existing Gale content may find the lack of cross-product search integration to be a problem.


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